Screening for colorectal cancer using fecal the occult blood test, Hemoccult
ABSTRACT Colorectal cancer is a leading cause of morbidity and mortality, especially in the Western world. The human and financial costs of this disease have prompted considerable research efforts to evaluate the ability of screening tests to detect the cancer at an early curable stage. Tests that have been considered for population screening include variants of the faecal occult blood test, flexible sigmoidoscopy and colonoscopy. Reducing mortality from colorectal cancer (CRC) may be achieved by the introduction of population-based screening programmes.
To determine whether screening for colorectal cancer using the faecal occult blood test (guaiac or immunochemical) reduces colorectal cancer mortality and to consider the benefits, harms and potential consequences of screening.
Published and unpublished data for this review were identified by: Reviewing studies included in the previous Cochrane review; Searching several electronic databases (Cochrane Library, Medline, Embase, CINAHL, PsychInfo, Amed, SIGLE, HMIC); and Writing to the principal investigators of potentially eligible trials.
We included in this review all randomised trials of screening for colorectal cancer that compared faecal occult blood test (guaiac or immunochemical) on more than one occasion with no screening and reported colorectal cancer mortality.
Data from the eligible trials were independently extracted by two reviewers. The primary data analysis was performed using the group participants were originally randomised to ('intention to screen'), whether or not they attended screening; a secondary analysis adjusted for non-attendence. We calculated the relative risks and risk differences for each trial, and then overall, using fixed and random effects models (including testing for heterogeneity of effects). We identified nine articles concerning four randomised controlled trials and two controlled trials involving over 320,000 participants with follow-up ranging from 8 to 18 years.
Combined results from the 4 eligible randomised controlled trials shows that participants allocated to screening had a 16% reduction in the relative risk of colorectal cancer mortality (RR 0.84, CI: 0.78-0.90). In the 3 studies that used biennial screening (Funen, Minnesota, Nottingham) there was a 15% relative risk reduction (RR 0.85, CI: 0.78-0.92) in colorectal cancer mortality. When adjusted for screening attendance in the individual studies, there was a 25% relative risk reduction (RR 0.75, CI: 0.66 - 0.84) for those attending at least one round of screening using the faecal occult blood test.
Benefits of screening include a modest reduction in colorectal cancer mortality, a possible reduction in cancer incidence through the detection and removal of colorectal adenomas, and potentially, the less invasive surgery that earlier treatment of colorectal cancers may involve. Harmful effects of screening include the psycho-social consequences of receiving a false-positive result, the potentially significant complications of colonoscopy or a false-negative result, the possibility of overdiagnosis (leading to unnecessary investigations or treatment) and the complications associated with treatment.
- SourceAvailable from: Lindsay C Kobayashi
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- "Colorectal cancer (CRC) is the second largest cause of cancer death in the UK (16,000 deaths per year) (NHS, 2013) and in 2011 was the third most common cancer in men (23,171 cases) and women (18,410 cases) (Cancer Research UK, 2014). Early detection through screening has been shown to be cost-effective (Tappenden et al., 2007) and effective in reducing CRC mortality (Hewitson et al., 2007; Schoen et al., 2012). "
ABSTRACT: Colorectal cancer (CRC) is the second largest cause of cancer death in the UK. Since 2010, CRC screening based on Faecal Occult Blood testing has been offered by the NHS in England biennially to all persons age 60 to 69 years. Several studies have demonstrated a gradient in uptake using area-level markers of socio-economic status (SES), but few have examined the individual-level contributors to the gradient. We aimed to quantify the extent of SES inequality in CRC screening uptake in England using individual-level data, and to identify individual factors associated with this inequality. We used data from 1,833 participants (aged 61-69) in Wave 5 (collected in years 2010/11) of the English Longitudinal Study of Ageing (ELSA) eligible for having been sent at least one CRC screening invitation. Uptake was defined by self-report of ever having been screened as part of the National Screening Programme. We assessed socio-economic inequality using the corrected concentration index of uptake against SES rank, which was derived by regressing a range of SES markers against net non-pension household wealth. Other demographic and health-related variables were included in the analysis. Factors associated with inequality were measured using concentration index decomposition. There was a significant pro-rich gradient in screening uptake (concentration index: 0.16, 95% CI:0.11-0.22), mostly explained within our model by differences in non-pension wealth (38.7%), partner screening status (15.9%), sickness/disability (13.5%), and health literacy (8.5%). Interventions aimed at reducing inequalities in CRC screening uptake should focus on improving acceptability of screening in populations with low levels of education and literacy barriers.Social Science & Medicine (1967) 06/2015; 134. DOI:10.1016/j.socscimed.2015.04.010
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- "In another five topics in which a statistically significant benefit had been seen in one trial, other trials had also been performed. Cochrane reviews showed a statistically significant survival benefit for biannual fecal occult blood testing  but not for PSA screening . "
ABSTRACT: Objectives To evaluate the effects of diagnostic testing on patient outcomes in a large sample of diagnostic randomized controlled trials (D-RCTs) and to examine whether the effects for patient outcomes correlate with the effects on management and with diagnostic accuracy. Study Design and Setting We considered D-RCTs that evaluated diagnostic interventions for any condition and reported effectiveness data on one or more patient outcomes. We calculated odds ratios for patient outcomes and outcomes pertaining to the use of further diagnostic and therapeutic interventions and the diagnostic odds ratio (DOR) for the accuracy of experimental tests. Results One hundred forty trials (153 comparisons) were eligible. Patient outcomes were significantly improved in 28 comparisons (18%). There was no concordance in significance and direction of effects between the patient outcome and outcomes for use of further diagnostic or therapeutic interventions (weighted κ 0.02 and 0.09, respectively). The effect size for the patient outcome did not correlate with the effect sizes for use of further diagnostic (r = 0.05; P = 0.78) or therapeutic interventions (r = 0.18; P = 0.08) or the experimental intervention DOR in the same trial (r = −0.24; P = 0.51). Conclusion Few tests have well-documented benefits on patient outcomes. Diagnostic performance or the effects on management decisions are not necessarily indicative of patient benefits.Journal of clinical epidemiology 06/2014; 67(6). DOI:10.1016/j.jclinepi.2013.12.008 · 3.42 Impact Factor
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- "In Canada, colorectal cancer (CRC) is the third most common cancer diagnosis and the second most common cause of death due to cancer (12% of all cancer deaths in 2012) . Prevention and early detection of CRC is possible through routine fecal occult blood test (FOBT) screening of individuals 50 to 74 years of age [2,3] as it has been estimated that if 70% of eligible Canadians completed an FOBT every two years, followed up by colonoscopy for positive FOBTs, the CRC mortality rate could be reduced by 17% [4,5]. Uptake of fecal occult blood test screening in Canada and Manitoba are sub-optimal. "
ABSTRACT: Evaluation of the effectiveness of a patient decision aid (nurse-managed telephone support line and/or colorectal cancer screening website), distributed to patients by their family physician, in improving fecal occult blood test (FOBT) colorectal cancer screening rates. A pragmatic, two arm, cluster randomized controlled trial in Winnipeg, Manitoba, Canada (39 medical clinic clusters; 79 fee-for-service family physicians; 2,395 average risk patients). All physicians followed their standard clinical screening practice. Intervention group physicians provided a fridge magnet to patients that facilitated patient decision aid access. Primary endpoint was FOBT screening rate within four months. Multi-level logistic regression to determine effect of cluster, physician, and patient level factors on patient FOBT completion rate. ICC determined. Family physicians were randomized to control (n = 39) and intervention (n = 40) groups. Compared to controls (56.9%; n = 663/1165), patients receiving the intervention had a higher FOBT completion rate (66.6%; n = 805/1209; OR of 1.47; 95% confidence interval 1.06 to 2.03; p < 0.02). Patient aid utilization was low (1.1%; 13/1,221) and neither internet nor telephone access affected screening rates for the intervention group. FOBT screening rates differed among clinics and physicians (p < 0.0001). Patients whose physician promoted the FOBT were more likely to complete it (65%; n = 1140/1755) compared to those whose physician did not (51.1%; n = 242/470; p < 0.0001; OR of 1.54 and 95% CI of 1.23 to 1.92). Patients reporting they had done an FOBT in the past were more likely to complete the test (70.6%; n = 1141/1616; p < 0.0001; 95% CI 2.51 to 3.73) than those who had not (43%; n = 303/705). Patients 50–59 years old had lower screening rates compared to those over 60 (p < 0.0001). 75% of patients completing the test did so in 34 days. Despite minimal use of the patient aid, intervention group patients were more likely to complete the FOBT. Powerful strategies to increase colorectal cancer screening rates include a recommendation to do the test from the family physician and focusing efforts on patients age 50–59 years to ensure they complete their first FOBT. Trial registration Trial registration number: clinicaltrials.gov identifier NCT01026753.BMC Cancer 04/2014; 14(1):263. DOI:10.1186/1471-2407-14-263 · 3.36 Impact Factor